Biomedical Engineering and Bioengineering Commons^™

Advancing Fluorescent Contrast Agent Recovery Methods For Surgical Guidance Applications, Brook Kennedy Byrd

Dartmouth College Ph.D Dissertations

Fluorescence-guided surgery (FGS) utilizes fluorescent contrast agents and specialized optical instruments to assist surgeons in intraoperatively identifying tissue-specific characteristics, such as perfusion, malignancy, and molecular function. In doing so, FGS represents a powerful surgical navigation tool for solving clinical challenges not easily addressed by other conventional imaging methods. With growing translational efforts, major hurdles within the FGS field include: insufficient tools for understanding contrast agent uptake behaviors, the inability to image tissue beyond a couple millimeters, and lastly, performance limitations of currently-approved contrast agents in accurately and rapidly labeling disease. The developments presented within this thesis aim to address such …

Small-Separation Speckle Contrast Optical Spectroscopy For Intraoperative Assessment Of Parathyroid Glands Viability During Thyroid Surgery, Connor Berger

Symposium of Student Scholars

The parathyroid glands (PTGs) are often damaged during thyroid surgeries due to a lack of methods identifying PTGs and assessing their viability. Damage to PTGs can cause hypocalcemia, a deficiency of calcium in the body. This complication can lead to detrimental consequences with economic burden. The surgeon’s current method of viability assessment is qualitative and subjective. Our technical solution is to employ an optical technique called speckle contrast optical spectroscopy (SCOS) that noninvasively quantifies the blood flow index (Db) of biological tissues at deep tissue levels (>1cm). The goal of this project is to verify SCOS at small source-detector-separation …

Six-Dimensional Single-Molecule Imaging With Isotropic Resolution Using A Multi-View Reflector Microscope, Oumeng Zhang, Zijian Guo, Yuanyuan He, Tingting Wu, Michael D. Vahey, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Imaging of both the positions and orientations of single fluorophores, termed single-molecule orientation-localization microscopy, is a powerful tool for the study of biochemical processes. However, the limited photon budget associated with single-molecule fluorescence makes high-dimensional imaging with isotropic, nanoscale spatial resolution a formidable challenge. Here we realize a radially and azimuthally polarized multi-view reflector (raMVR) microscope for the imaging of the three-dimensional (3D) positions and 3D orientations of single molecules, with precisions of 10.9 nm and 2.0° over a 1.5-μm depth range. The raMVR microscope achieves 6D super-resolution imaging of Nile red molecules transiently bound to lipid-coated spheres, accurately resolving …

The Role Of Generative Adversarial Networks In Bioimage Analysis And Computational Diagnostics., Ahmed Naglah

Electronic Theses and Dissertations

Computational technologies can contribute to the modeling and simulation of the biological environments and activities towards achieving better interpretations, analysis, and understanding. With the emergence of digital pathology, we can observe an increasing demand for more innovative, effective, and efficient computational models. Under the umbrella of artificial intelligence, deep learning mimics the brain’s way in learn complex relationships through data and experiences. In the field of bioimage analysis, models usually comprise discriminative approaches such as classification and segmentation tasks. In this thesis, we study how we can use generative AI models to improve bioimage analysis tasks using Generative Adversarial Networks …

Mango Surface Color Features Measurement Using Digital Image Processing, Md Towfiqur Rahman, Goutom Kumar, Md Abdul Momin

Biological Systems Engineering: Papers and Publications

Summary

Postharvest processing of agricultural produce is still done the conventional way in Bangladesh. Manual grading of agricultural produce, especially fruits and vegetables, is laborious and costly due to acute shortage of labor during the peak season, as well as difficulty maintaining the product quality. Machine vision system (MVS) applications are widely used nowadays as a non-destructive and cost-effective technology for automatically grading and sorting large volumes of produce in the packing house according to size, shape, color, texture, and surface defects. In this study, a simple MVS was constructed measuring different color features of mango fruit surface as a …

Image-Based Cancer Diagnosis Using Novel Deep Neural Networks, Hosein Barzekar

Theses and Dissertations

Cancer is the major cause of death in many nations. This serious illness can only be effectivelytreated if it is diagnosed early. In contrast, biomedical imaging presents challenges to both clinical institutions and researchers. Physiological anomalies are often characterized by modest modifications in individual cells or tissues, making them difficult to detect visually. Physiological anomalies are often characterized by slight abnormalities in individual cells or tissues, making them difficult to detect visually. Traditionally, anomalies are diagnosed by radiologists and pathologists with extensive training. This procedure, however, demands the participation of professionals and incurs a substantial expense, making the classification of …

Seeing The Big Picture: System Architecture Trends In Endoscopy And Led-Based Hyperspectral Subsystem Intergration, Craig M. Browning

<strong> Theses and Dissertations </strong>

Early-stage colorectal lesions remain difficult to detect. Early development of neoplasia tends to be small (less than 10 mm) and flat and difficult to distinguish from surrounding mucosa. Additionally, optical diagnosis of neoplasia as benign or malignant is problematic. Low rates of detection of these lesions allow for continued growth in the colorectum and increased risk of cancer formation. Therefore, it is crucial to detect neoplasia and other non-neoplastic lesions to determine risk and guide future treatment. Technology for detection needs to enhance contrast of subtle tissue differences in the colorectum and track multiple biomarkers simultaneously. This work implements one …

Development Of Optical Coherence Tomography Angiography System For Mouse Eye Imaging And Measurement Of Vasodilation, Yilin Li

McKelvey School of Engineering Theses & Dissertations

Optical coherence tomography angiography (OCTA) is broadly known as a non-invasive technology that allows examining the retinal and choroidal vasculatures, alternative to fluorescein angiography. In this study, we have developed an optical coherence tomography (OCT) system for imaging the mouse eye. We measure the retinal thickness, which is 216.53um. We apply OCTA to characterize the quantitative change in vessel diameter and the perfusion density of the retina after the wild-type mice are administered the adenosine or inhale carbon dioxide. Comparing the images acquired one minute and 5 minutes after the injection or CO₂ inhalation with the baseline, distinct changes …

Iron Nanoparticles For Magnetic Imaging Applications, Aleia Williams

Masters Theses

Extensive research on iron oxide nanoparticles for various applications including nanomedicine, energy applications, environmental remediation, and magnetic imaging have previously been performed. Many are currently FDA approved as magnetic resonance imaging contrast agents and tracers for magnetic particle imaging applications. Magnetic properties of such materials are crucial to obtain good contrast and resolution. However, studies have shown the magnetic properties of iron oxide nanoparticles are less in comparison to those found in pure iron nanoparticle.

This research involves the synthesis and characterization of iron nanoparticles for applications in magnetic resonance imaging contrast agents, magnetic particle imaging tracers, and therapeutic agents …

Development And Validation Of A Three-Dimensional Optical Imaging System For Chest Wall Deformity Measurement, Nahom Kidane

Electrical & Computer Engineering Theses & Dissertations

Congenital chest wall deformities (CWD) are malformations of the thoracic cage that become more pronounced during early adolescence. Pectus excavatum (PE) is the most common CWD, characterized by an inward depression of the sternum and adjacent costal cartilage. A cross-sectional computed tomography (CT) image is mainly used to calculate the chest thoracic indices. Physicians use the indices to quantify PE deformity, prescribe surgical or non-surgical therapies, and evaluate treatment outcomes. However, the use of CT is increasingly causing physicians to be concerned about the radiation doses administered to young patients. Furthermore, radiographic indices are an unsafe and expensive method of …

Neroimaging Of Brain Activaion Using Diffuse Optical Tomography, Jingyu Huang

USF Tampa Graduate Theses and Dissertations

This research has two parts. The first part focuses on the use of non-invasive imaging technique, diffuse optical tomography (DOT), to study the brain activation during the stimulation in the clinical room. It further extends the application of DOT by using it to monitor the hemodynamic response during the TMS stimulation in different parameters. Diffuse optical tomography (DOT) is based on NIR light that exploits the relative transparency of biological tissue. The part two and three extends the application in the hospital for delirium patient study and arm muscle dystrophy by adding the sources and detectors to monitor the brain …

Development Of A Near-Full-View Angle Coverage Photoacoustic Tomography System And Its Application Towards Optical Fluence Distribution Imaging, Lawrence Cm Yip

Electronic Thesis and Dissertation Repository

Photoacoustic tomography (PAT) is a widely explored hybrid imaging modality combining advantages of ultrasound and optical imaging. However, on the acoustic detection side, limited-view angle coverage and limited-detector bandwidth are common key issues in PAT systems that result in unwanted artifacts. While analytical and simulation studies of limited-view artifacts are extensive, experimental setups capable of comparing limited-view to an ideal full-view case are lacking. Due to the lack of PAT systems capable of artifact-free full-view imaging, applications for such a system have also been left unexplored.

A custom ring-shaped detector array was assembled and mounted to a 6-axis robot, which …

Model-Based Determination Of The Synchronization Delay Between Mri And Trajectory Data., Paul Ioan Dubovan, Corey Allan Baron

Robarts Imaging Publications

PURPOSE: Real-time monitoring of dynamic magnetic fields has recently become a commercially available option for measuring MRI k-space trajectories and magnetic fields induced by eddy currents in real time. However, for accurate image reconstructions, sub-microsecond synchronization between the MRI data and field dynamics (ie, k-space trajectory plus other spatially varying fields) is required. In this work, we introduce a new model-based algorithm to automatically perform this synchronization using only the MRI data and field dynamics.

METHODS: The algorithm works by enforcing consistency among the MRI data, field dynamics, and receiver sensitivity profiles by iteratively alternating between convex optimizations for (a) …

Using Shg Directionality To Characterize Collagen Alteration In Breast Cancer Tumor Microenvironment And Its Prognostic Applications, Betelhem Solomon Abay

Electronic Theses and Dissertations

Although breast cancer is a growing health concern worldwide, the challenge to minimize mortality rate partly comes from the heterogeneity in its pathological characteristics. The tumor microenvironment is a complex hub of signaling cascades that plays a key role for the progression of cancer to develop to metastatic stage. The extracellular matrix (ECM), as a major component of the tumor microenvironment, contains signatures that have cues to understand tumor progression. Here, the unique microstructural collagen alterations specific to reactive stromal/tumor cell interactions and interactions of reactive stromal fibroblasts with different tumor cell types MCF7A and MDA-MB-231 were investigated. Early alterations …

Evaluation And Clinical Implementation Of A Dual-Energy Ct Stopping-Power Ratio Mapping Technique For Proton-Therapy Treatment Planning, Maria Jose Medrano Matamoros

McKelvey School of Engineering Theses & Dissertations

Proton radiotherapy has the potential to treat tumors with better conformal dose distribution than competing modalities when the rapid dose falloff at the end of the proton-beam range is correctly aligned to the edge of the clinical target volume (CTV). However, its clinical potential is dependent on the accurate localization of the Bragg-peak position from predicted stopping-power ratio maps. The method that is most commonly used in today’s clinical practice for predicting stopping-power ratio (SPR) consists of a stoichiometric calibrationtechnique based on single-energy CT (SECT) for direct estimation of patient-specific SPR distribution from vendor-reconstructed Hounsfield Unit (HU) images. Unfortunately, this …

Labeling Melanoma Cells With Black Microspheres For Improved Sensitivity In Detection Via Photoacoustic Flow Cytometry, Tori Kocsis

Electronic Theses and Dissertations

Melanoma is an aggressive form of skin cancer known for developing into metastatic disease. Current clinical diagnostics, including medical imaging and tissue biopsy, provide a poor prognosis since the cancer is in the late stages of disease progression. In recent years, photoacoustic flow cytometry has allowed for the detection of circulating melanoma cells within patient blood samples in vitro. Although this method exploits the naturally-produced melanin within the cells, it has only successfully detected highly-pigmented melanoma cell lines. Since various forms of melanoma exist, each with varying melanin concentrations, this research aims to provide a novel method for detecting lightly-pigmented …

Improving The Performance And Evaluation Of Computer-Assisted Semen Analysis, Ji-Won Choi

Dissertations

Semen analysis is performed routinely in fertility clinics to analyze the quality of semen and sperm cells of male patients. The analysis is typically performed by trained technicians or by Computer-Assisted Semen Analysis (CASA) systems. Manual semen analysis performed by technicians is subjective, time-consuming, and laborious, and yet most fertility clinics perform semen analysis in this manner. CASA systems, which are designed to perform the same tasks automatically, have a considerable market share, yet many studies still express concerns about their accuracy and consistency. In this dissertation, the focus is on detection, tracking, and classification of sperm cells in semen …

Assessing Structural And Functional Brain Alterations And Work-Related Fatigue In Non-Hyposmic And Hyposmic Covid-19 Survivors, Rakibul Hafiz

Dissertations

In the year 2019, life began to change at the advent of a global pandemic caused by the novel coronavirus. Mask mandates and mass vaccinations have mitigated the effects significantly, yet cases keep rising with new variants, especially, in densely populated countries, like India. Recent neuroimaging evidence shows the virus can attack the central nervous system (CNS). However, exactly which brain regions undergo structural and functional changes remain largely unknown. Many patients experience 'loss of/reduced sense of smell' (i.e., hyposmic) and an alarming number of survivors develop persistent symptoms ('long-COVID') for several months after initial infection. Fatigue is the most …

Erythrocyte Deformability In Response To Glucose Using Liquid Crystals, Jayden Goff

Biomedical Engineering Undergraduate Honors Theses

The worldwide prevalence of diabetes mellitus is rapidly increasing with about 9.3% of the adult population living with the disease. People with diabetes have trouble regulating their blood glucose levels which typically leads to hyperglycemia. Under normal physiological conditions, erythrocytes can undergo deformations in response to shear stress when passing through capillaries with a smaller diameter. Poorly managed hyperglycemia can lead to the glycosylation of erythrocyte membrane proteins and hemoglobin. This glycosylation leads to increased rigidity of the cells along with decreased deformability in response to mechanical stress; therefore, these cells have a higher susceptibility of getting stuck in the …

3d Volumetric Mapping Of Tissue Properties Via A Catheter-Scale Microendoscope Imaging System, Andrew Stark

Biomedical Engineering Undergraduate Honors Theses

The study of tumor microvasculature is an important area of interest for research and clinical communities; however, there are significant limitations in the clinical characterization of the tumor microenvironment. Optical methods offer quantitative real-time measurement of tissue structure and perfusion and can be miniaturized for deployment endoscopically into previously inaccessible locations. However, conventional optical methods (i.e., optical coherence tomography, white light endoscopy, etc.) gives limited information about tissue perfusion while the diameter of various optical probes along with the complexity of scanning mechanisms make it difficult to access certain areas. In this study, a new technique for characterizing the tumor …

The Influence Of Mmp14 On Angiogenesis In Chemotherapy-Treated Tumors, Abdussaboor Muhammad

Biomedical Engineering Undergraduate Honors Theses

Colorectal cancer is the third most common cancer in the world, and it is the fourth most common cause of cancer related death (1). There have been many significant advancements regarding the treatment of cancer which aim to shrink the size of tumors in patients. However, there is still more that needs to be understood about the many different factors that play a role in colorectal cancer development.

Angiogenesis is the process of forming new blood vessels from existing ones and it requires breaking down and remodeling of the extracellular matrix (ECM) in order to allow endothelial cells to migrate …

Sequential Illumination In A Tomographic Microendoscopic Probe For Imaging Tumor Microvasculature, Zachariah Neumeier

Biomedical Engineering Undergraduate Honors Theses

Knowledge of colorectal cancer biology is improving how we approach cancer treatment. Specifically, the tumor microenvironment and abnormal angiogenesis are of particular interest. Optical methods are a prime candidate for research of the tumor microenvironment due to their ability to quantitively assess tissue structure and perfusion in real time. Particularly, the “transport scattering regime” has been identified as a method of obtaining high-resolution images and reflectance spectroscopy data; this light scattering regime has been demonstrated compatible with endoscopic imaging systems. In this study, a proof-of-concept optical imaging system is presented, capable of resolving absorbers within scattering turbid media using a …

Determination Of Tissue-Level Changes In Tumors That Are Indicative Of Metastasis Using Optical Spectroscopy, Sanidhya D. Tripathi

Biomedical Engineering Undergraduate Honors Theses

Breast cancer, accounting for 12% of all new cancer cases, is one of the leading causes of death in women worldwide. Although patient survival has improved over the years, metastatic spread to other organ sites and not due to the primary tumor is the most common form of tumor recurrence, accounting for 90% deaths. Hypoxia is a common hallmark of solid tumors and is linked with metastasis, therapeutic resistance, and poor patient survival. Defined as a state of decreased oxygen availability, cells under hypoxia have an increased rate of genetic mutation, local invasion, and resistance to treatment such as radiation …

The Effects Of Metronomic And Maximum-Tolerated Dose Chemotherapy In Colorectal Cancer Angiogenesis: A Combined Approach Using Endoscopic Diffuse Reflectance Spectroscopy And Mrna Expression, Ariel Isaac Mundo Ortiz

Graduate Theses and Dissertations

Colorectal cancer (CRC) continues to be one of the most incident and deadliest types of cancer worldwide. Chemotherapy has proven effective to reduce tumor burden for CRC patients, but there are several disadvantages associated with the use of mainstay maximtolerated dose (MTD) chemotherapeutic strategies. Metronomic chemotherapy (MET) has been developed as an alternative that addresses the shortcomings of maximum-tolerated dose chemotherapy but so far its effectiveness as a neoadjuvant strategy for CRC has not been explored.

This dissertation uses a combined optics and molecular biology approach (using diffuse reflectance spectroscopy and mRNA expression) to study the changes in angiogenesis and …

Machine Learning Approaches For Early Prediction Of Hypertension., Heba Elsayed Mohamed Kandil

Electronic Theses and Dissertations

Hypertension afflicts one in every three adults and is a leading cause of mortality in 516, 955 patients in USA. The chronic elevation of cerebral perfusion pressure (CPP) changes the cerebrovasculature of the brain and disrupts its vasoregulation mechanisms. Reported correlations between changes in smaller cerebrovascular vessels and hypertension may be used to diagnose hypertension in its early stages, 10-15 years before the appearance of symptoms such as cognitive impairment and memory loss. Specifically, recent studies hypothesized that changes in the cerebrovasculature and CPP precede the systemic elevation of blood pressure. Currently, sphygmomanometers are used to measure repeated brachial artery …

Investigating The Impact Of Hypoxia On Reactive Oxygen Species Generation Within Murine Breast Cancer Cells, Jared Mcpeake

Biomedical Engineering Undergraduate Honors Theses

When cancer metastasizes from a primary tumor site to secondary site through the bloodstream or lymph, the cancer becomes more difficult to treat. For this reason, it is vital to study what indicates the metastatic potential of a tumor. Current research has shown that cell lines with high metastatic potential display increased levels of metabolic adaptability over their nonmetastatic counterparts after undergoing hypoxic conditions. One method of assessing this adaptability is to measure the concentration of reactive oxygen species (ROS) produced by the cells while undergoing oxidative stress. In highly adaptable metastatic cells, an increase of ROS buildup within the …

Clot Analogs For The Development Of Improved Treatment Methods In Ischemic Stroke, Charles A. Rieth

Biomedical Engineering Undergraduate Honors Theses

According to the CDC, nearly 800,000 individuals experience stroke each year in the United States [1]. Greater than 70% of strokes are of ischemic etiology and involve the occlusion of key arteries in the cardiovascular system [2]. Tissue plasminogen activator (IV-tPA) is the current gold standard for thrombolytic approaches [3]; however, this therapeutic is only effective between 3 and 4.5 hours from the patient’s last know well [4]. As a result, less than 5% of acute ischemic stroke patients receive IV-tPA. In order to increase the viability of AIS treatment as a whole, it is essential that thrombolytic techniques are …

Nonlinear Optical Microscopy Assessment Of Tissue Structure And Chondrocyte Viability Of Articular Cartilage, Michael Le

All Theses

Articular cartilage functions to protect the ends of bones by providing a surface that can withstand compressive forces and minimize friction during movement. Collagen fibers form the organizational backbone of the extracellular matrix (ECM) in cartilage. Proteoglycans within the ECM function to retain water and provide the tissue with the swelling pressure needed to withstand compressional forces. Chondrocytes, the only type of cell found in articular cartilage, produces these collagen fibers and proteoglycans to maintain the tissue structure and function. Significant injuries to articular cartilage can damage the chondrocytes and disrupt their ability to maintain homeostasis in the tissue. Therefore, …

Analysis Of An Existing Method In Refinement Of Protein Structure Predictions Using Cryo-Em Images, Maytha Alshammari, Jing He, Willy Wriggers, Jiangwen Sun

College of Sciences Posters

Protein structure prediction produces atomic models from its amino acid sequence. Three-dimensional structures are important for understanding the function mechanism of proteins. Knowing the structure of a given protein is crucial in drug development design of novel enzymes. AlphaFold2 is a protein structure prediction tool with good performance in recent CASP competitions. Phenix is a tool for determination of a protein structure from a high-resolution 3D molecular image. Recent development of Phenix shows that it is capable to refine predicted models from AlphaFold2, specifically the poorly predicted regions, by incorporating information from the 3D image of the protein. The goal …

Wavelet-Based Automatic Breast Segmentation For Mammograms, Basel White

Honors College

As part of a first of its kind analysis of longitudinal mammograms, there are thousands of mammograms that need to be analyzed computationally. As a pre- processing step, each mammogram needs to be converted into a binary (black or white) spatial representation in order to delineate breast tissue from the pectoral muscle and image background, which is called a mammographic mask. The current methodology for completing this task is for a lab member to manually trace the outline of the breast, which takes approximately three minutes per mammogram. Thus, reducing the time cost and human subjectivity when completing this task …